Electronics Forum | Thu May 20 14:32:06 EDT 2010 | davef
First, what's wrong with some dewetting of conformal coating on component bodies? Second, there are chemistries that might be able to remove silicone mold release, but cleaning the chemistry is not easy without affecting the whole board, as you impl
Electronics Forum | Tue Nov 27 19:42:58 EST 2001 | mparker
Dave - will placing MELF's in SMT eliminate the original problem? Is the flux aggressive enough to clean mold release agents from the component manufacturer? Good point about LT reliability, just wondering what would happen if glue was eliminated fr
Electronics Forum | Thu Feb 17 15:01:23 EST 2005 | davef
We're not familiar with your DYMAX #984-LVUF. The problem is not with your conformal coating. The problem is with your 0805 [and not all of 0805, probably just those from a specific supplier]. This lack of coverage of components is called dewetting
Electronics Forum | Thu May 20 08:51:29 EDT 2010 | jry74
A lot of our dewetting is happening on plastic body components, such as ICs. When they are manufactured, the molding process requires a mold release to make the part release after molding. Usually, the release agent is silicon based, but you can't
Electronics Forum | Tue May 25 11:37:50 EDT 2010 | davef
Where on the assembly is the dewetting occurring? Factors that influence dewetting usually involve non-ionic contamination such as: * Residues from board manufacture including silicone surfactants from solder resist & HASL rinse contamination * Comp
Electronics Forum | Sat Sep 25 03:44:38 EDT 2004 | GS
Thanks Davef, unfotunately in order to keep TIC of PBA inside our customer TIC requirements, we have to pre-wash (DI water only)connectors before assembly. Too high level of Br- continuosly get released by connectors molding compound. Our assemb
Electronics Forum | Wed May 19 19:46:41 EDT 2010 | jry74
I am experiencing sporatic de-wettting issues, so I have been thinking about ways to clean fully assembled circuit boards that have open switches, contacts, etc. I also suspect that that plastic bodied components have residual silicone mold release
Electronics Forum | Fri Dec 10 12:24:46 EST 2010 | davef
Causes of dewetting in conformal coating. Factors that influence dewetting usually involve non-ionic contamination such as: * Residues from board manufacture including silicone surfactants from solder resist & HASL rinse contamination * Component res
Electronics Forum | Tue Jun 02 14:32:58 EDT 1998 | Chris Fontaine
We have experienced poor adhesion of acrylic conformal coating to plastic bodied IC�s. The observed symptoms of this are a blistering or lifting of the coating at the surface of the component, although peel testing has revealed that this is not alwa
Electronics Forum | Tue Jun 02 15:53:32 EDT 1998 | Earl Moon
| We have experienced poor adhesion of acrylic conformal coating to plastic bodied IC�s. The observed symptoms of this are a blistering or lifting of the coating at the surface of the component, although peel testing has revealed that this is not al
.gif)
